Lisdexamfetamine dimesylate is approved and marketed in the United States for the treatment of attention-deficit hyperactivity disorder in pediatric patients. The active compound lisdexamfetamine contains D-amphetamine covalently linked to the essential amino acid L-lysine. Controlled release of D-amphetamine, a psychostimulant, occurs following administration of lisdexamfetamine to a patient. The controlled release has been reported to occur through hydrolysis of the amide bond linking D-amphetamine and L-lysine.
A procedure for making lisdexamfetamine hydrochloride is described in U.S. Pat. No. 7,223,735 to Mickle et al. (hereinafter Mickle). The procedure involves reacting D-amphetamine with (S)-2,5-dioxopyrrolidin-1-yl 2,6-bis(tert-butoxycarbonylamino)hexanoate to form a lysine-amphetamine intermediate bearing tert-butylcarbamate protecting groups. This intermediate is treated with hydrochloric acid to remove the tert-butylcarbamate protecting groups and provide lisdexamfetamine as its hydrochloride salt. However, this procedure suffers several drawbacks that are problematic when carrying out large scale reactions, such as manufacturing scale, to prepare lisdexamfetamine.
The need exists for new methods and compositions for preparing lisdexamfetamine and salts thereof, particularly in high enantiomeric purity. The invention addresses this need and has other related advantages.